Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Internal Insect Morphology Circulation System Organization: Humans – closed Our circulatory system consists of a heart and a series of tubes (arteries and veins) intimately associated with every cell Insects – open Blood Cavity (Hemocoel) Entire open area (here in white) is a blood filled cavity called the Hemocoel. The insect circulatory system: Hearts and Ostia - Ostia are one-way valves that allow blood to enter heart. It is then forced out via the aorta. Aorta The 9 hearts Hearts Aorta Generalized circulation path of blood in insects. Not a very efficient system and would not work for humans but is effective for insects because of the limited functions of the circulatory system Circulatory system functions: •Transport - food •Protection – immune system •Hydraulic – inflates wings •Respiration (minor) •Thermoregulation – cools/warms Blood characteristics: 1) Color 2) Contents Sodium, Potassium, Calcium, Magnesium & other salts, water Digestive System Consists of 3 regions: 1) Foregut 2) Midgut 3) Hindgut Foregut : esophogus Conducts, stores, guides foods Midgut : small intestine Major site of food absorption Enzyme production Hindgut : large intestine Transports waste from body Reabsorbs water and eliminates Uric acid Salivary Glands: Function as a food solvent, digestive enzymes, produce glue, silk, plant hormones (IAA). Digestive Process •Intestinal: normal digestive process •Extra-intestinal: Digestion outside the body by regurgitation of enzymes onto or into food before ingestion •Microbial aids – termites and bacteria necessary to digest cellulose Adaptations to a Liquid Diet Aphids and Scale Insects Produce “Honey dew” First Stomach with filter chamber Second Stomach enzymes added here Rectum - Excess water and some sugars leave body Excretory System: Maintains internal environment suitable for survival of the insect It does this through two structures/processes: 1) Malpighian tubules = Eliminates nitrogenous waste from the blood 2) Hindgut = Regulates salt and water and Uric Acid (H20) Ventilation: Respiration Tracheal System: a system of air tubes that carry gases to and from body tissues. Trachael system of an insect. There are three parts to the Tracheal System: 1) Spiracles: external openings of the tubes 2) Tracheae: transport air through body 3) Taenida: spiral bands of the exoskeleton in the wall of trachea – add strength Mode of action: Diffusion Pumps Efficiency – diffusion works well for insects because they are small Spiracles Tomato Horn Worm Taenidia are spiral bands of the exoskeleton in the wall of trachea. Nervous System Brain - Ventral Nerve Cord - Ganglia and axons throughout body Brain Subesophageal Ganglion Thoracic Ganglia Ventral Nerve Cord Ganglia and axons of the insect body. Brain Role: •Receive and integrate sensory data •Little coordination like in humans •Other functions - walking, flying, mating are under control of nearby ganglia Metamorphosis Nightclubs Insect Growth and Development •Exoskeleton limits growth •Shedding exoskeleton (ecdysis) - necessary to grow and/or change shape •Ecdysis involves loss of: Outside body covering, the foregut, the hindgut and tracheal system This much area is “digested” and recycled into new exoskeleton. Cicada nymph casing – very thin and brittle •Instars - the insect between molts •Generations – egg to adult. How many per year? > 2 per year = pest Metamorphosis – Change in shape or form Regulated by 3 hormones: •Ecdysone - molting hormone •Juvenile Hormone •Brain Hormone (PTTH) = prothoracicotrophic hormone Types of Metamorphosis: 1)Simple metamorphosis Juvenile (young) insects look much like what they will look like as adults-silverfish, bristletails Types of Metamorphosis: 2)Incomplete -- Ephemeroptera – Mayflies Eggs Nymph Naiads Adults Hemiptera – True bugs Gradual Metamorphosis Types of Metamorphosis: 4) Complete – Lepidoptera, Coleoptera, Diptera, Hymenoptera Eggs Larva Pupa Adult Reasons for Insect Success • Flight • Complete Metamorphosis • Elytra Wing Cover End of Basic Entomology Part II